Systems and methods for deviation detection, information extraction and obligation deviation detection

ABSTRACT

The present disclosure is directed towards systems and methods for detecting deviations between documents and portions thereof, extracting information from text and detecting deviations between obligations. Information is extracted by identifying defined terms and their definitions in input text as well as by identifying portions of different input texts relevant to a point of interest and detecting deviations in those portions between the different input texts.

This application for letters patent disclosure document describesinventive aspects that include various novel innovations (hereinafter“disclosure”) and contains material that is subject to copyright, maskwork, and/or other intellectual property protection. The respectiveowners of such intellectual property have no objection to the facsimilereproduction of the disclosure by anyone as it appears in publishedPatent Office file/records, but otherwise reserve all rights.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. ProvisionalApplication Nos. 62/965,516, filed Jan. 24, 2020; 62/965,520, filed Jan.24, 2020; 62/965,523, filed Jan. 24, 2020; and 62/975,514, filed Feb.12, 2020, which are hereby incorporated by reference in theirentireties.

BACKGROUND

The present innovations generally address tools for detecting deviationsamong documents and portions thereof, extracting information fromdocuments and portions thereof, and detecting deviations betweenobligations in documents and portions thereof.

One practical application of these concepts is in the review of legalcontracts and the differences between the clauses that they contain. Forexample, during negotiation lawyers often may need to look at redlinedchanges from a counterparty and determine whether those are acceptableor not. During an acquisition of a company, for example, due diligenceoften needs to be performed on a large set of contracts to determinerisks and deviations from standard contract templates of the acquiringcompany. As another example, users may desire to extract key terms andclauses from a certain document (e.g. lease agreement) and look forlegal issues that could provide risks for their clients. A commonsubtask in the review process often involves comparing a document to anagreed upon standard document of the same type and flagging significantdeviations, which is a time-consuming, often fully manual process.

While there exist basic document comparison tools, most employtechniques that only consider simple syntactic differences. As a result,these tools only work for comparing very similar documents that aredrafted from the same document template. In particular, most documentcomparison tools . . . :

-   -   (a) do not deal well with major changes in formatting or        reordering of paragraphs and sentences [showing them as addition        plus deletion instead],    -   (b) overwhelm the user with minor syntactic differences that do        not constitute any differences in meaning (e.g. “three months”        vs “3 months”), and    -   (c) are not able to measure the type or degree of difference,        making it difficult to categorize or prioritize changes.

Accordingly, the present inventions address the need for improvements incomputer functionality to detect deviations among documents and portionsthereof, extract information from documents and portions thereof, anddetect deviations between obligations in documents and portions thereof.

In order to develop a reader's understanding of the innovations,disclosures have been compiled into a single description to illustrateand clarify how aspects of these innovations operate independently,interoperate as between individual innovations, and/or cooperatecollectively. The application goes on to further describe theinterrelations and synergies as between the various innovations; all ofwhich is to further compliance with 35 U.S.C. § 112.

BRIEF SUMMARY

The present invention provides a system and method for structure and/orheader extraction.

In one aspect, a method for detecting deviations comprises receiving astandard document and a review document, splitting apart sentences ineach of the standard document and review document, matching a sentencefrom the review document to a sentence from the standard document, anddetecting deviations in a review sentence from a standard sentencematched to the review sentence.

In one example, the method further comprises selecting, based on contentof at least one of review sentence and the matched standard sentence, adeviation detection tool from among a group of more than one deviationdetection tools to perform the deviation detection for those sentences.

In another example, the sentence preprocessed before they are matched byconverting all characters to lower case.

In another example, the sentence preprocessed before they are matched byremoving any numbered or lettered list items at the beginning of thesentence.

In another example, the sentence preprocessed before they are matched byremoving any numbers as tokens.

In another example, the sentences are matched based at least on acomparison of at least one of the length of the sentences, characterlength of the sentences without spaces, average length of the words inthe sentences, number of words in the sentences, and number of commonwords in the sentences.

In another example, the method further comprises outputting anindication to a user interface if a review sentence is not matched to asentence in the standard document or is a sentence in the standarddocument is not matched to a review sentence.

In another example, the method further comprises selecting, based on acloseness of the match between a review sentence and its matchedstandard sentence, a deviation detection tool from among a group of morethan one deviation detection tools to perform the deviation detectionfor those sentences.

In another example, deviations between a review sentence and itsmatching sentence from the standard document are not detected if acloseness of the match is less than a predetermined closeness threshold.

In another example, the method further comprises matching more than onesentence from the review document to one sentence from the standarddocument wherein deviations are detected between the more than onesentence from the review document as a whole and the one matchingsentence from the standard document.

In another example, the method further comprises matching one sentencefrom the review document to more than one sentence from the standarddocument wherein deviations are detected between the one sentence fromthe review document and the matching more than one sentence from thestandard document as a whole.

In another example, the method further comprises outputting indicationsof a detected deviation to a user interface only if the detecteddeviation does not involve only the addition or deletion of a wordcontained on a predetermined list of words to be ignored.

In another aspect, a method for extracting information, comprisesreceiving an input text, splitting the input text into n-grams whileretaining a case of words as a feature, for each n-gram, determiningwhether it is a capitalized concatenated sequence of words andcalculating a frequency of the n-gram's appearance in the input textrelative to how rarely the n-gram is used in general use, identifying asa defined term each n-gram that is a capitalized concatenated sequenceof words and has a relative frequency above a predetermined threshold,identifying a definition of each defined term from the input text, anddisplaying the definition of a defined term while also displaying aportion of the input text in which the defined term appears but that isdifferent from a portion of the input text identified as the definitionof the defined term.

In one example, the method further comprises cleaning the input textbefore the input text is split into n-grams by at least removingpunctuation marks except for a predetermined plurality of punctuationmarks to be retained.

In another example, the definition of a defined term is not displayeduntil a view of the input text is scrolled to display the portion of theinput text in which the defined term appears but that is different froma portion of the input text identified as the definition of the definedterm.

In another example, defined terms are displayed together with the inputtext even if the defined terms are not present in a currently displayedportion of the input text.

In another example, the defined terms are highlighted where they appearin a display of the input text.

In another aspect, a method for extracting information comprisesreceiving a standard text and a review text, analyzing the standard textand the review text to identify portions of those texts relevant to aninput point of interest, displaying in a user interface a portion oftext identified in the review text as relevant to the point of interestwhile also displaying any deviations therein from a portion of textidentified in the standard text as being relevant to the point ofinterest.

In another example, the point of interest is one of a question, a topic,a named fact and a defined term.

In another example, the deviations are not displayed until a user clickson the displayed portion of text identified in the review text as beingrelevant to the point of interest.

In another example, the portion of text identified in the standard textas being relevant to the point of interest is displayed upon a userclicking the portion of text identified in the review text as beingrelevant to the point of interest.

In another example, multiple portions of text are identified in thestandard text as being relevant to the point of interest and aredisplayed upon a user clicking the portion of text identified in thereview text as being relevant to the point of interest. In one example,any deviations between the portion of text identified in the review textas being relevant to the point of interest and each of the multipleportions of text are identified in the standard text as being relevantto the point of interest and are displayed.

In another example, the analysis of the standard text and the reviewtext to identify portions of those texts relevant to an input point ofinterest includes using words of the input point of interest as querywords and estimating a likelihood of those query words in documentlanguage models representative of portions of the reference text andportions of the standard text.

In another example, points of interest are displayed on the userinterface and the portion of text identified in the review text asrelevant to a particular point of interest is not displayed until a userclick s on the display of that particular point of interest.

In another aspect, a method for detecting deviations in obligations,comprises receiving a standard sentence and a review sentence,classifying the standard sentence and review sentence, identifying anyactors, obligations and restrictions in the standard sentence and reviewsentence, and identifying any differences between actors, obligationsand restrictions of the standard sentence and review sentence.

In one example, the identification of any obligations includes selectingand applying an obligation detection tool from among a plurality ofobligation detection tools based on a classification of the sentence towhich the tool is to be applied.

In another example, the method further comprises identifying a modalityof each obligation identified and identifying any difference betweenobligation modalities of the standard sentence and the review sentence.

In another example, the method further comprises if multiple obligationsare identified in a sentence, splitting the sentence into sentenceportions such that each sentence portion includes at most oneobligation.

In another example, identifying restrictions includes identifying thepresence in a sentence of any of a predetermined plurality ofrestriction trigger words.

In another example, the method further comprises highlighting anidentified obligation in a user interface.

In another example, the method further comprises compiling identifiedobligations into a dictionary and passing the dictionary back to arequestor of the obligation deviation detection.

In another example, the method further comprises preprocessing thestandard sentence and review sentence by replacing any agents referencedas anaphora with a different text string to which the anaphora refers.

In another example, identifying differences between agents includescalculating a non-binary similarity metric between agents identified inthe standard sentence and in the review sentence.

In another example, multiple review sentences are received, obligationsare identified in the multiple review sentences, and the method furthercomprises identifying the most similar obligation identified in themultiple review sentences to an obligation identified in the standardsentence. In one example, if an obligation is not identified in themultiple review sentences for which a similarity to the obligationidentified in the standard sentence is above a predetermined threshold,an indication is displayed on a user interface that the obligationidentified in the standard sentence has been deleted from the multiplereview sentences.

In another example, multiple standard sentences are received,obligations are identified in the multiple standard sentences, and themethod further comprises identifying the most similar obligationidentified in the multiple standard sentences to an obligationidentified in the review sentence and if an obligation is not identifiedin the multiple standard sentences for which a similarity to theobligation identified in the review sentence is above a predeterminedthreshold, an indication is displayed on a user interface that theobligation identified in the review sentence has been added to themultiple standard sentences.

In another example, identifying differences between restrictionsincludes calculating a non-binary similarity metric between restrictionsidentified in the standard sentence and in the review sentence and onlyindicating a difference in restriction if the similarity metric betweenrestrictions is below a predefined threshold.

In another example, the method further comprises displaying the standardsentence along with the review sentence on a user interface andhighlighting any identified differences between the identified actors,obligations and restrictions. In one example, the method furthercomprises displaying an indication, written in words, of any identifieddifferences between the identified actors, obligations and restrictions.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate various non-limiting, example,innovative aspects in accordance with the present descriptions:

FIG. 1 depicts a flow chart of document comparison steps according to anexemplary embodiment of the present innovations.

FIG. 2 depicts examples of types of deviations detected and detectableby exemplary embodiments of the present innovations.

FIG. 3 depicts examples of types of obligation changes and deviationsdetected and detectable by exemplary embodiments of the presentinnovations.

FIG. 4 depicts an exemplary distribution of similarity scores betweenmatching and non-matching sentence pairs.

FIG. 5 depicts a graph of metrics dependent on threshold set.

FIG. 6 depicts a representation of a training dataset using exemplaryavailable feature sets.

FIG. 7 presents the top 10 most important features for the gradientboosting classifier that performs the best for the low deviation leaseexample.

FIG. 8 presents the top 10 most important features in the case of thehigh deviation lease example.

FIG. 9 presents an example of multiple sentences of a standard documentbeing matched to one sentence of a review document.

FIG. 10 depicts a flow chart of document comparison steps according toan exemplary embodiment of the present innovations.

FIG. 11 shows a heatmap representation of a matrix for the alignment oftwo exemplary sentences.

FIG. 12 shows an example of retracing the best segment alignment ofexemplary sentences.

FIG. 13 shows an example of the output of an exemplary user interface.

FIG. 14 shows several examples approaches used to convert text tofeatures.

FIG. 15 shows an example of architecture of a model with a fullyconnected network.

FIG. 16 shows an exemplary user interface depicting the extraction andpresentation of keyphrases in a text being reviewed.

FIG. 17 shows an example of a legal document containing a “OperatingCosts” defined term.

FIG. 18 shows an example of a pop-up box presented to a user in a userinterface.

FIG. 19 shows exemplary regex patterns that may be deployed to identifyand extract defined terms.

FIG. 20 shows an example of a user interface relaying various namedfacts from a document being reviewed.

FIG. 21 shows an example of another user interface relaying variousdefined terms from a document being reviewed.

FIG. 22 shows an example of a user interface depicting the result of aquestion analysis and answer extraction tool.

FIG. 23 is a flow chart showing an exemplary approach to obligationclassification and extraction according to an exemplary embodiment.

FIG. 24 shows a dependency parse structure of an exemplary sentence.

FIG. 25 is a flow chart showing an exemplary approach to obligationcomparison and change and deviation detection according to an exemplaryembodiment.

FIG. 26 shows an example of a standard lease term compared against areview lease with multiple changes detected according to an exemplaryembodiment.

DETAILED DESCRIPTION

Embodiments of systems and methods for detecting deviations amongdocuments and portions thereof, extracting information from documentsand portions thereof, and detecting deviations between obligations indocuments and portions thereof are described herein. While aspects ofthe described systems and methods can be implemented in any number ofdifferent configurations, the embodiments are described in the contextof the following exemplary configurations. The descriptions and detailsof well-known components and structures are omitted for simplicity ofthe description, but would be readily familiar to those having ordinaryskill in the art.

The description and figures merely illustrate exemplary embodiments ofthe inventive systems and methods. It will thus be appreciated thatthose skilled in the art will be able to devise various arrangementsthat, although not explicitly described or shown herein, embody theprinciples of the present subject matter. Furthermore, all examplesrecited herein are intended to be for illustrative purposes only to aidthe reader in understanding the principles of the present subject matterand the concepts contributed by the inventors to furthering the art, andare to be construed as being without limitation to such specificallyrecited examples and conditions. Moreover, all statements hereinreciting principles, aspects, and embodiments of the present subjectmatter, as well as specific examples thereof, are intended to encompassall equivalents thereof.

In general, the systems and methods described herein may relate toimprovements to aspects of using computers to detect deviations amongdocuments and portions thereof, extract information from documents andportions thereof, and detect deviations between obligations in documentsand portions thereof. These improvements not only improve thefunctioning of how such a computer (or any number of computers employedin extracting structure and header information from documents) is ableto operate to serve the user's document analysis goals, but alsoimproves the accuracy, efficiency and usefulness of the deviationdetection, information extraction and obligation deviation detectionresults that are returned to the user.

The tools described herein are particularly suited to legal documentsand are generally discussed in that context, however it will beappreciated that many other types of documents, texts and users willbenefit from the inventive tools disclosed and claimed herein.

In one aspect, the present innovations provide a novel mechanism toautomatically compare a given document to an agreed upon standarddocument of the same type. The system identifies significant linguisticdifferences and flags these as potential legal issues to users forreview. In contrast to existing tools, the system can handle reorderingof sentences and paragraphs, and categorizes changes, allowing forprioritization and triage.

In one example, document comparison may be performed at the clause orsentence level and executed in three key stages as shown in FIG. 1 anddescribed in more detail below.

In the pre-processing stages, we use techniques for text splitting 10(e.g., python nitk's sent_tokenize) and text similarity measures 12(e.g. tf-idf vectorization+cosine similarity). The former allows forcomparison and review at the sentence level. The latter aligns sentencesfrom the standard document with sentences from the review document in acomputationally cheap way to scope and reduce computation time of morecomplex comparison.

The aim of this task is to identify missing/additional sentences whencomparing two clauses and find matches for sentences which arenon-missing. Before this can be achieved, clauses are split into smallerchunks, usually sentences. This task is represented by the sentencesplitting step 10 depicted in FIG. 1.

Sentence Splitting

The input into this task are two clauses, one from the reviewed document(for example, manually selected by the user via text highlighting) andone from a corresponding standard document. The output is the linking ofsentences between the two documents.

An illustrative example of the sentence splitting task 10 based on oneclause is shown in Table 1. In reality, this step could be performed ontwo clauses in parallel. An example for the sentence matching task isshown below.

TABLE 1 Whole Eviction of tenant Clause 14. The Landlord reserves theright to evict the tenant if the tenant fails to comply with the termsof this lease. (a) If the tenant fails to pay the rent within 5 businessdays of the date when it is due, the tenant is liable for eviction. (b)The tenant must also pay all costs, including reasonable attorney fees,related to the eviction and the collection of any moneys owed to thelandlord, along with the cost of re-entering, re-renting, cleaning andrepairing the premises. Sentence s0 Eviction of tenant Splitting s1 14.The Landlord reserves the right to evict the tenant if the tenant failsto comply with the terms of this lease. s2 (a) If the tenant fails topay the rent within 5 business days of the date when it is due, thetenant is liable for eviction. s3 (b) The tenant must also pay allcosts, including reasonable attorney fees, related to the eviction andthe collection of any moneys owed to the landlord, along with the costof re-entering, re-renting, cleaning and repairing the premises.

In order to perform the sentence splitting, one approach is to splitclauses on paragraphs (for example, as identified by a “\n” symbol informatted text) first before using the punkt tokenize implementation ofnitk, which splits strings of texts at sentence boundaries. In anotherexample, a period “.” is used to split text into sentences.

Table 2 shows another example of clause text and subsequent sentencesplitting.

TABLE 2 Standard 25. Repairs Clause— 25.1 The Tenant shall keep theProperty clean and tidy and in good repair and Raw text condition andshall ensure that any Lifts and Service Media within and exclusivelyserving the Property are kept in good working order. 25.2 The Tenantshall not be liable to repair the Property to the extent that anydisrepair has been caused by an Insured Risk, unless and to the extentthat the policy of insurance of the Property has been vitiated or anyinsurance proceeds withheld in consequence of any act or omission of theTenant, any undertenant or their respective workers, contractors oragents or any person on the Property with the actual or impliedauthority of any of them. Standard s0 25. Repairs Clause— s1 25.1 TheTenant shall keep the Property clean and tidy and in good repairSentence and condition and shall ensure that any Lifts and Service Mediawithin and Splitting exclusively serving the Property are kept in goodworking order. s2 25.2 The Tenant shall not be liable to repair theProperty to the extent that any disrepair has been caused by an InsuredRisk, unless and to the extent that the policy of insurance of theProperty has been vitiated or any insurance proceeds withheld inconsequence of any act or omission of the Tenant, any undertenant ortheir respective workers, contractors or agents or any person on theProperty with the actual or implied authority of any of them. ReviewTenant's covenants for repair Clause— 22.1 The Tenant shall put and keepthe Property clean and tidy and in good and Raw Text substantial repairand shall ensure that any Service Media within and exclusively servingthe Property is kept in good operating order. 22.2 The Tenant shall notbe liable to repair the Property to the extent that any disrepair hasbeen caused by an Insured Risk, unless and to the extent that the policyof insurance of the Property has been vitiated or any insurance proceedswithheld in consequence of any act or omission of the Tenant, anyundertenant or their respective workers, contractors or agents or anyperson on the Property with the actual or implied authority of any ofthem. 22.3 The Tenant shall clean the inside and outside of all windowsat the Property as often as is reasonably necessary. 22.4 The Tenantshall replace any plate glass or other window that becomes cracked orbroken as soon as practicable. Review r0 Tenant's covenants for repairClause— r1 22.1 The Tenant shall put and keep the Property clean andtidy and in good Sentence and substantial repair and shall ensure thatany Service Media within and Splitting exclusively serving the Propertyis kept in good operating order. r2 22.2 The Tenant shall not be liableto repair the Property to the extent that any disrepair has been causedby an Insured Risk, unless and to the extent that the policy ofinsurance of the Property has been vitiated or any insurance proceedswithheld in consequence of any act or omission of the Tenant, anyundertenant or their respective workers, contractors or agents or anyperson on the Property with the actual or implied authority of any ofthem. r3 22.3 The Tenant shall clean the inside and outside of allwindows at the Property as often as is reasonably necessary. r4 22.4 TheTenant shall replace any plate glass or other window that becomescracked or broken as soon as practicable.

After the splitting, every clause may be assigned a clause ID and everysentence may be assigned a sentence id. A sentence id from the standardalways starts with the character ‘s’ followed by the number/order of thesentence in the clause (i.e. the first sentence from the standarddocument would be labelled ‘s0’ or sometimes ‘s1’). Similarly, asentence id from the review document will start with the character ‘r’and again followed by the number that represents the order of thesentence in the clause text. We are assuming that matching sentences arefound in the matching clauses. In a scenario where the matchingsentences are identified in distinct clause types, then the clauses thatcontain all matching sentences may be merged to one and assigned asingle clause ID. We later modified the sentence id convention toinclude the clause id as well, to allow cross-clause comparison i.e. amatching sentence can be found in different clauses within the document(i.e. sentence id ‘s1’ of clause id ‘CC’ became ‘s1CC’).

Table 3 and Table 4 present a matching schema of the example clauses ofTable 2. The matching can occur in two directions: from the standarddocument to the review document (Table 3) and from the review documentto the standard document (Table 4). A sentence can be matched to one ormultiple sentences. In the scenario of multi-sentence matching, thematched sentence ids are separated by comma (i.e. s1->r1, r2, r3 meansthat the sentence s1 of the standard is matching to all three sentencesr1, r2, r3 of the review document).

TABLE 3 Comparison Clause name Reference from to Repairs CC s1 r1Repairs CC s2 r2

TABLE 4 Comparison Clause name Reference from to Repairs CC r1 s1Repairs CC r2 s2 Repairs CC r3 None Repairs CC r4 None

In one example, sentences are preprocessed according to one or more ofthe following operations: lower case, removal of numbers as tokens andremoval of any numbered or lettered list items (i.e. (a), 12.1) orsimilar at the beginning of the sentence.

Basic features between sentences may be compared, for example:

-   -   1. Length of sentence 1    -   2. Length of sentence 2    -   3. Difference between the lengths    -   4. Character length of sentence1 without spaces    -   5. Character length of sentence2 without spaces    -   6. Average length of word in sentence1    -   7. Average length of word in sentence2    -   8. Number of words in sentence1    -   9. Number of words in sentence2    -   10. Number of common words in sentence1 and sentence2    -   11. Difference of sets

Fuzzy features may be generated by the fuzzywuzzy python library whichis based on the difflib.ratio implementation but calling the method withdifferent subsets of tokens from the original sentence. The featuresconsidered between sentences may include, for example, any of thefollowing:

-   -   1. QRatio    -   2. WRatio    -   3. Partial Ratio    -   4. Partial Token Set Ratio    -   5. Partial Token Sort Ratio    -   6. Token Set Ratio    -   7. Token Sort Ratio

A tf-idf vectorizer may be trained on the corpus from training datasetsusing unigrams and bigrams. After the generation of the sentence vectors(size=7869), vector distances may be calculated using any one or more ofCosine, Euclidean and Manhattan metrics.

Singular Value Decomposition (SVD) lower dimensionality vectors may alsobe generated (n_components=180, accounting for >0.85 of variance). Forexample, the Truncated SVD implementation of the sklearn python librarymay be used. In addition, bag of words (bow) based vectors may begenerated by training a count vectorizer. The count vector distanceswere then calculated using one or more of the following metrics:Jaccard, Overlap coefficient, Dice, and Jaccard+Overlap coefficient.

To generate a domain specific language model, a gensim python librarymay be used to train a word2vec language model on a set of exemplarydocuments, for example US lease documents. In one example, the size ofthe resulting vocabulary was ˜15K which is limited but the model couldalready capture domain specific word similarities better than the spacygeneric model (i.e. property—premises, landlord—lessor, Table 5).

TABLE 5 Word 1 Word 2 w2v Similarity Score Spacy Score Property Premises0.70 0.55 Landlord Lessor 0.94 0.48 Tenant Lessee 0.92 0.64 LandlordTenant 0.91 0.83 Includes Including 0.72 0.75 Pay Return 0.45 0.42Improvement Inspection 0.36 0.38 Leave Run 0.25 0.42

In addition, different ways of generating the sentence embedding fromthe word embeddings may be used. For example, possible techniquesinclude i) summing the word vectors, ii) averaging the word vectors andiii) using tf-idf weighting scheme of the words in the sentence togenerate the sentence vector (for the effects of the different sentenceembedding approaches on the classifier score, see Table 9). Based on thesentence vectors, one or more features may be generated including, forexample:

-   -   1. Cosine distance    -   2. Euclidean distance    -   3. Manhattan distance    -   4. Canberra distance    -   5. Minkowski distance    -   6. Braycurtis distance    -   7. Skew    -   8. Kurtosis    -   9. Wmd (word mover's distance)

A representation of the training dataset using all available featuresets is represented in FIG. 6.

Besides exploration of the performance of the different feature sets,additional exploration was performed on the effect of the training data.For example, training a classifier using high deviation gold data mayresult in better ability to predict similarity of high deviating leases.Therefore, the specific training dataset used is highlighted whenrelevant.

In one example, Leave One Group Out cross validation (sklearn) may beperformed to allow for clause-based stratifications using the groups asthe clauses. Hyperparameter grid search may be performed according toeach classifier type.

The classifiers' performance may examined for two different documenttype examples: a low-medium deviation lease and a high deviation lease.As shown in Table 8, for the low deviation example, the best classifieris a gradient boosting classifier trained on all three leases,substantially outperforming the benchmark based on tf-idf vector cosinedistance (one single feature with a threshold). For the high deviationexample, the best model was also a gradient boosting classifier but thistime trained on the training subset only, which is also characterized bya high degree of deviation. For both classifiers, the feature set usedfor training contains the basic, tf-idf based distances, countvectorizer based distances, and w2v vector based distance features.

TABLE 8 Best models per lease type. The training data are separated inthe three leases used (1: Nitya-dummy US, 2: Louise Practical Law UK, 3:Louise DWF UK). The performance is also presented according to the twodifferent test datasets (AL2-low deviation, LouiseJan19LS-highdeviation). Low-Medium Deviation Lease High Deviation Lease Matching F1F1 Classifier Features Training* Refit Precision Recall Score PrecisionRecall Score Benchmark tfidf 1, 2, 3 f1 0.45 0.91 0.60 0.64 0.26 0.37cosine Gradient Basic, 1, 2, 3 Precision 1.00 0.85 0.92 0.57 0.05 0.09boosting3 tfidf/bow/ w2v dist Gradient Basic, 3 f1 0.37 0.65 0.47 0.50.34 0.41 boosting4 tfidf/bow/ w2v dist

FIG. 7 presents the top 10 most important features for the gradientboosting classifier that performs the best for the PL to PL, US, AL2lease example (low deviation example). In FIG. 8, the 10 most importantfeatures in the case of the high deviation example are presented. Herew2v based features are more prominent which could be expected as in thehigh deviation example it is the semantic similarity, rather than thelexical, that plays a more decisive role in the matching. The tfidfbased features remain however as the most important ones.

Different methods of sentence embeddings may also affect the classifierperformance. Table 9 displays the different scores obtained usingdifferent strategies for sentence embeddings i.e. mean vs sum of wordvectors, and using of the tfidf weighting scheme or it not. Overall,there are no dramatic effects from the different sentence embeddingstrategies but the mean embedding with tfidf weighting slightlyoutperforms the other methods in terms of precision and it was thereforethe preferred choice. Alternatively, the simple sum of the word vectorsgives a slightly higher F1 score.

TABLE 9 PL to WL, UK, PL to PL, US, AL2 LouiseJan19LS (low deviation)(high deviation) Matching F1 F1 Classifier Features Training* RefitPrecision Recall Score Precision Recall Score Benchmark tfidf cosine 1,2, 3 f1 0.45 0.91 0.60 0.64 0.26 0.37 Gradient w2v dist- 3 f1 0.79 0.700.74 0.51 0.23 0.31 boosting mean with tfidf weighting Gradient w2vdist- 3 f1 0.78 0.66 0.72 0.51 0.23 0.31 boosting mean Gradient w2vdist- 3 f1 0.46 0.69 0.58 0.46 0.25 0.32 boosting sum with tfidfweighting Gradient w2v dist- 3 f1 0.78 0.74 0.76 0.46 0.25 0.32 boostingsum

The skill of the sentence splitting and sentence matching algorithms aremeasured separately. When measuring the success of the sentence matchingalgorithm, we give it the perfectly split sentences as an input. Withinthe sentence matching task, we separate between the matching vsnon-matching sentences classification and additional/missing vsnon-missing sentence classification.

The matching vs non-matching sentences classification task tells uswhether two sentences in different documents have comparable content andshould therefore be matched up for further deviation analysis. For thistask, we would prefer showing too many matches rather than too few.

The additional/missing vs non-missing sentence classification task onthe other hand tries to identify sentences which either only occur inthe standard but not in the reviewed document (a missing sentence) orthe other way around (an additional sentence). For this task, it isimportant not to miss out on any missing/additional sentences as thiscould lead to undesired consequences for the end-user.

When reporting on the overall skill in terms of user experience, thesentence splitting and matching skills would have to be combined. Thedetails on how those metrics are calculated is described in more detailbelow.

Sentence/Content Matching

Documents or texts to be analyzed can vary wildly in length, from entiredocuments (e.g., contracts, legal briefs) to paragraphs (contractclauses) to individual sentences. For instance, the extent to which theoriginal and amended regulations are different, or how similar are twosentences—these are just two examples from a wide variety of cases thatlend themselves to text comparison.

In the context of contract analysis, content matching may requirecomparing fragments of text between a standard and a review contract.The text fragments are typically sentences discovered in the contracts,but can be as short as just a phrase or as long as multiple sentences.

Content/Keyphrase Matching

At a high level, the “classic” machine learning approaches comprisefeature representations such as tf-idf and count vectors, which aresparse and are well suited for modeling by algorithms such as SVM andrandom forest. These approaches were followed by neural networks wherewords are represented by dense vectors, or word embeddings, for exampleword2vec or fastText. These representations have performed well inneural network architectures, including RNNs, which consider wordposition in a sentence. More recently, contemporary language models suchas Bert and XLNet fused feature learning and training into one model,with the embedding block in the model followed by a task-specific block,such as classification.

One important aspect of successful text similarity models in practice isdomain adaptation. Training a model specific to the domain of interest,be it medical or legal, typically leads to a better performing model.

In one exemplary model, several approaches are used to convert text tofeatures, shown in FIG. 14. All of them were trained on 11,000 exemplarycommercial leases. Each feature converts a text of arbitrary length(e.g. a sentence) into a vector of fixed length.

Vocabulary for TF-IDF was learned from 1-, 2- and 3-grams in leases.Stopwords were omitted and vocabulary size was restricted to 10,000 mostfrequent tokens.

For the topic model, a non-negative matrix factorization (NMF) model waslearned on the leases. The input features for the model were binary,using the same vocabulary as for TF-IDF but with binary indicators ofwhether a token was present in the document. 20 components (topics) werekept.

A list of keyphrases may be extracted from the exemplary commercialleases and used as the data input to a trained word2vec keyphraseembeddings analyzer. For example, for a pair of sentences, allkeyphrases in both sentences are embedded and cosine similaritiesbetween all keyphrase embeddings from the first sentence and all fromthe second are calculated. The top 10 most similar scores are used asfeatures.

SIF (Smooth Inverse Frequency) is an approach to sentence embeddingbased on embeddings of words in that sentence. This algorithm calculatesa weighted average of word embeddings, projects them into alower-dimensional space using PCA and removes the first principalcomponent that accounts for most variations. The authors' explanation isthat weighting “smoothens” the score by accounting for words that occurout of context, and removing the first principal component filters outthe effect of the most common words.

In one example, word embedding analysis was trained on the exemplary11,000 commercial leases. In one example, only weighting may beperformed without reducing dimensionality. As a result, this feature mayoutput a vector of size 100 for each sentence pair, for example.

A sequence-to-sequence autoencoder may be trained on sentences from theexemplary 11,000 commercial leases. For example, a random sample of500,000 sentences was extracted and used for training. Sentences werepadded or truncated to 50 words maximum. The architecture of both theencoder and the decoder was an LSTM cell unrolled over 50 time steps.The output of the last step of the encoder was used as therepresentation, or embedding, of the input sentence. The size of theembedding was set to 100.

Tokens in the input sentence were embedded using word embeddings trainedon the commercial leases.

None of the features described above typically retain the informationabout the lengths of the two sentences. In practice, however, afive-word phrase could be compared to a 100-word passage. To retain thisinformation, one may divide the number of words in the shorter sentenceby the number of words in the longer sentence.

In one implementation, these features may be fed into training algorithmmodels. In a demonstrative example, features are fed into differentmodels: a random forest model (e.g., with 2500 estimators), a fullyconnected neural network (e.g., with three hidden layers: 2048, 512 and32 units), and a Bert model. The first two models used the featuresdescribed in the above. FIG. 15 shows the architecture of the model withthe fully connected network. With the random forest model, the output oftext-to-feature conversion is fed into a random forest model instead.

Sentence Matching

The two examples below illustrate the difference between two exemplaryclassification tasks we considered in terms of sentence matching. Table10 shows the “gold” data we used as a baseline for the match vs no-matchclassification task and subsequent quality scoring.

TABLE 10 Gold data for the match vs no-match classification task. ‘r’ isused for a sentence from the reviewed document and ‘s’ for the standarddocument. 1 = matching sentences and 0 = non-matching sentencesaccording to a manual review. Clause From To Gold Label A r0 s0 1 A r0s1 1 A r0 s2 0 A r0 s3 0 A r1 s0 0 A r1 s1 0 A r1 s2 0 A r1 s3 0 A r2 s00 A r2 s1 0 A r2 s2 1 A r2 s3 0

Table 11 shows the gold data we have for the missing/additional vsnon-missing classification task. It essentially contains the sameinformation as Table 2, but a label is given per sentence in thereviewed document rather than per pairwise comparison. In this example,sentence r1 is identified as an additional sentence as it does not matchup with any sentences in the standard document.

TABLE 11 Gold data for the missing/additional sentence identificationtask. ‘r’ is used for a sentence from reviewed document and ‘s’ for thestandard document. 1 = missing/additional sentence and 0 = non-missingsentence. Clause From To Gold Label A r0 s0, s1 0 A rl None 1 A r2 s2 0

Table 12 below shows how the decision whether or not two sentences arematched up was made. In order to obtain this information, similarityscores between all sentence pairs within a clause were calculated. Thesimilarity score is based on cosine similarity of the correspondingtf-idf vectors (including bigrams). The sentences are pre-processed byputting everything into lower case, removing numbers as tokens, andremoving any list numberings (e.g. (a) at the beginning of a sentence).Stopwords were not removed as tokens, as this did not seem to improvethe classification task.

In the example below, we compute similarity scores between threesentences from the reviewed clause (r0-r2) and four sentences from thestandard clause (s0-s3). The sentence comparisons are grouped into fourclasses depending on where their similarity scores fall.

TABLE 12 Matching diagram obtained from comparing three sentences fromthe reviewed clause (r0-r2) with four sentences from the standard clause(s0-s3). Score Threshold r0 r1 r2 Label 1 T1 s0 (Near) Exact Match — s1s2 Good Match — s1 — T2 s2 s0 Possible Match — s1 — T3 s3 s0 s3 No match(=missing/additional) — s3 0 s2

In one implementation, threshold T1 may be set to 0.9(near_exact_match_threshold), T2 to 0.36 (miss_add_sim_threshold), andT3 to 0.15 (matching_threshold), measured in terms of cosine similarity(based on tf-idf vectors). T1 and T3 may be chosen manually, but mayalso be set based on an optimizing of a computational cost function. Oneimportant threshold is T2, which was optimized based on a pre-definedcost function (maximum F1 score in this case).

The setting of the similarity thresholds may be guided by a statisticalanalysis. For example, as shown in FIG. 4, the distribution ofsimilarity scores between matching and non-matching sentence pairs isdepicted. An optimal threshold may be defined on this data, for examplethe T2 threshold shown. The optimal value for threshold T2 is obtainedby moving the threshold along the x-axis and calculating F1 scores alongthe way, as shown in FIG. 5. The threshold with maximum F1 score may beselected as the threshold T2. A high F1 score signals that matching andnon-matching sentence pairs can be well-separated. Orange sentence pairsto the left of the optimal threshold and blue sentence pairs to theright of the threshold are misclassified examples.

In addition to splitting text into sentences, it may be beneficial tobreak sentences into sub-sentences for the purposes of the presentanalysis. For example, long sentences may be constructed from multipleclauses separated by semicolons. In these instances, the clauses mayfind matches more readily on an individual basis than the entiresentence would.

In addition, short portions of text that initially are split as asentence may be discarded to improve matching efficiency. For example,headers comprising a small number of words ending a period may bealgorithmically identified as a “sentence,” then they are not intendedto be a sentence of prose and are not meaningful in a document deviationreview activity.

Comparison Scoping

In the comparison scoping step 14, the system determines which parts ofthe document to compare further. Rather than running complex linguisticcomparison methods on each pair of sentences from the standard andreview clause, we only send pairs of sentences above a certain syntacticsimilarity threshold to the deviation detection routines 16. Each of thefour deviation detection submodules incorporate their own criteria forwhat is considered a suitable input, as discussed below.

Deviation Detection

A key part of the analysis is to map the similar sentences between thetwo documents to detect their deviations. Another importantfunctionality is to identify the missing/additional to the reviewdocument sentences when compared to the standard. The identification ofmissing/additional sentences is of high value for the customers as itcould highlight potential high risks. The two tasks of matching andmissing/additional detection are closely related in the sense that asentence without a match is eventually a missing/additional sentence.

As one example, using the examples shown in Table 4, differentapproaches may be employed based on the similarity score and resultsfound. For example, for a near exact match (e.g., r0->s0) a singlesentence word diff may be performed. In one implementation, near matcheslike s0 may be removed from subsequent comparisons other than with theirmatch like r0. As another example, reviewed clauses with no near exactor good matches (e.g., r1) may be flagged as an “additional sentence”with no good match, but all possible matches may be displayed to a userfor manual review. As another example, for reviewed clauses withmultiple good matches (e.g., r2->s2, s1), a multi-sentence word diff maybe performed on all good matches.

In another exemplary embodiment, the deviation detection modules take acollection of sentences from the review document and compare them tosimilar sentences and terms from the standard. Linguistic differencesbetween two contracts can vary in degree and kind of client risk/impactassociated with them. To surface these differences to the user, wecategorize the linguistic changes and distinguish between four classesof deviations as follows:

1. Missing/Additional Sentences,

2. Monitored Term Deviations,

3. Word Differences between Matching Sentence Pairs/Groups, and

4. Obligation Changes (incl. four different sub-categories)

Each type of deviation is identified through a separate text comparisonmethod, which we describe above and in further detail in the followingdescription. FIG. 2 provides representative, but non-limiting examplesof each type.

An important and often very significant type of deviation from an agreedupon standard is the addition or deletion of whole provisions, sentencesor even paragraphs. In order to support the user in identifying suchchanges, we added a missing/additional sentence classificationcomponent.

Missing/Additional Sentences

The missing/additional sentence classification component may beconfigured to classify each sentence from the review document as“additional” or not (meaning it “matches linguistically to a sentence inthe standard”) and each sentence from the standard document as “missing”or not. It uses the standard similarity metrics computed in thepre-processing step as features and standard classifiers (e.g. logisticregression) as decision mechanism.

A missing sentence is a sentence that is present in the review documentbut not in the standard document. An additional sentence is a sentencethat is present in the review document but not in the standard document.Following from the previous sections, a sentence of the standarddocument that has no match in the review document is a missing sentence,while a sentence of the review document that has no match in thestandard document is an additional sentence. As such, it is possible touse the classifiers trained in the previous section to identify theadditional/missing sentences by looking at which sentences where neverassigned a positive label by the classifier. In Table 13, the bestsentence matching classifiers of Table 8 are used to predict themissing/additional sentences.

TABLE 13 PL to WL, UK, PL to PL, US, AL2 LouiseJan19LS Add/Miss F1 F1Classifier Features Training* Refit Precision Recall Score PrecisionRecall Score Benchmark tfidf 1, 2, 3 f1 0.71 0.84 0.77 0.44 0.87 0.58cosine Gradient Basic, 1, 2, 3 Precision 0.74 0.95 0.83 0.37 1 0.54boosting tfidf/bow/ w2v dist Gradient Basic, 3 f1 0.60 0.76 0.67 0.450.82 0.58 boosting tfidf/bow/ w2v dist

Besides using the Sentence Matching Classifier for theadditional/missing sentence identification, a new classifier may becreated, specifically focused on the missing/additional task.

For the additional/missing sentence classifier the training data usedwere derived from the gold data described in the previous sections. Thepairwise comparisons dataset was generated and the sentences werepre-processed as described before. Subsequently, all sentences that haveat least one match got assigned to a negative class (not missing oradditional) and all sentences that did not have a single match wereassigned to a positive class.

Following, summary features were created based on the clause, directionand sentence id. More specifically, for each sentence (“from” column) aminimum distance to a sentence of the equivalent clause of thecomparison document may be determined and the median distance of the“from” sentence to all sentences of the equivalent clause in thecomparison document may be determined. We are basically trying tocapture the most similar sentence in the equivalent clause but also theoverall similarity of each sentence to the text in the equivalentcomparing clause. For this analysis, the feature sets that wereconsidered may be the ones that calculate the distances of the vectors:tfidf dist, bow dist and w2v dist (N=38).

Monitored/Named Fact/Term/Keyphrase Extraction and Deviation Analysis

In most review tasks, users often have a specific list of defined ormonitored terms and provisions to check for them in a document and howthey are represented. In order to support that part of a review, weinclude a mechanism for identifying deviations with regard to specificmonitored terms. For each clause, the users specify a list of words ortyped item (numbers or dates) for inclusion or exclusion from the clausebody. The system then checks for occurrence in the text and flags anydeviations accordingly.

Keyphrase extraction is an important means of automatically selecting aset of phrases that best summarize a given free text document.Keyphrases also provide semantic metadata that can improve theperformances of various tasks including question answering, documentclassification, etc.

The example shown in FIG. 16 shows how keyphrases can summarize a giventext. On the left-hand side, a free plain text is provided, once thekeyphrases extraction process is done, a list of key phrases isprovided—in this example, the phrases “Statutory sick pay”, “additionalsocial assistance benefits”, “self-employed workers”, “Europeanconvention” and “welfare secretary” are extracted. By only looking atthese phrases, one may conclude that the topic of the text is aboutbenefits related to sickness for self-employed workers in Europe.

As mentioned above, another benefit keyphrases provide is addingsemantic metadata to the document to improve the performance of varioustasks. It may be desirable to use keyphrases as features for theunderlying applications including question answering and contentmatching. Below is an illustration of how key phrases can be used asfeatures.

-   -   Input text: “someone who, immediately before a proposed        assignment, is either a guarantor of the Tenant's obligations        under this Lease or a guarantor of the obligations given by a        former tenant of this Lease under an AGA;”    -   Word as tokens: [‘proposed’, ‘obligations’, ‘is’, ‘an’, ‘Lease’,        ‘given’, ‘assignment’, ‘former’, ‘Tenant's’, ‘under’, ‘before’,        ‘someone’, ‘AGA’, ‘immediately’, ‘by’, ‘tenant’, ‘a’, ‘this’,        ‘of’, ‘guarantor’, ‘who,’, ‘either’, ‘the’, ‘or’]    -   Include Keyphrases as tokens: [‘proposed assignment’,        ‘obligations’, ‘is’, ‘an’, ‘this Lease’, ‘given’, ‘former        tenant’, ‘Tenant's’, ‘under’, ‘before’, ‘someone’, ‘AGA;’,        ‘immediately’, ‘by’, ‘a’, ‘of’, ‘guarantor’, ‘who,’, ‘either’,        ‘the’, ‘or’]

Note that some phrases (e.g., “this Lease”) may contain more informationrelated to the meaning of this text than the individual words whichmeans by using the phrases to represent the meaning of the text willgive more accurate results.

There are several possible approaches for keyphrase extraction. Forexample, in a rule-based linguistic approach, the rules are derived fromthe linguistic knowledge/features such as lexical feature, syntacticfeature, discourse feature, etc. Usually, it's more accurate but iscomputationally intensive and require domain knowledge in addition tolanguage expertise. In this approach, after identifying candidatephrases, a set of linguistic features can be applied to filter out thenoisy ones. One of the common linguistic features people use is parts ofspeech (POS) of the phrase constituents.

In another approach, a statistical approach, statistical featuresderived from the linguistic corpus are used. They are independent of thelanguage and domain of the corpus and typically only the availability ofa large amount of datasets can make it possible to achieve good results.In this approach, keyphrases may be extracted by calculating thestandard deviation of the distance between successive occurrences of aword as a parameter to quantify the self-attraction based on theintuition that important words of a text have a tendency to attract eachother and form clusters.

In another approach, a machine learning approach, supervised learningmethods are employed where the keyphrases are extracted from trainingdocuments to learn a model. This approach includes Naive Bayes, SupportVector Mchine, etc. These methods require a tagged document corpus whichmay be difficult to obtain. A keyphrase extraction algorithm may be abinary classifier based on the Baye's theorem. The algorithm may analyzethe input document on orthographic boundaries such as punctuation marks,newlines, etc. to find candidate phrases, and creates two features forthe phrases that are tf-idf and the first occurrence of them to fit intothe classifier.

In another approach, a domain-specific approach, backend knowledgerelated to the domain such as ontology and inherent structure of thatparticular corpus may be exploited to identify and extract keyphrases.For example, a contrastive approach to extract keyphrases may beemployed, especially from the underlying domain corpora. A contrastiveranking may be used that is based on the idea that keyphrases from thedomain should have different distributions from the ones obtained fromthe general corpus. The contrastive weight may be used to standout thedomain-specific keyphrases.

In still another approach, some of these other approaches may becombined and may be used in connection with an existing source of domainknowledge to customize the approach for a particular domain, for examplethe review of legal documents or contracts. In this approach, fourgeneral steps are executed:

-   -   1. Dictionary look-up: in a legal context, law dictionaries may        be used, for example (1) Black's Law dictionary which is a        publicly available legal dictionary of law definitions and terms        for over 100 years and (2) Novas Phrases dictionary which is a        proprietary dataset owned by Thomson Reuters to look up key        phrases from an underlying legal document.    -   2. Identify candidates: A rule-based feature is included and a        statistical feature is calculated for each multi-word term and a        set of candidates is chosen by setting up a threshold.    -   3. Filtering by linguistic patterns: A list of part-of-speech        patterns is created and candidates are filtered out that do not        follow the patterns.    -   4. Filtering by semantic similarity: The candidate set is        further filtered out by only keeping the ones that have high        semantic similarity with a list of predefined topics.

The key phrases identified from the first step are kept to the end whilethe candidate keyphrases identified through step two to step four arefiltered by the corresponding criteria.

In one example of a dictionary look-up operation, two law dictionariesare used to look up keyphrases for legal documents:

-   -   Black's Law Dictionary: The Black's Law Dictionary is a publicly        available and trusted legal dictionary of law definitions and        terms for over 100 years. The n-grams (n≥2) may be extracted        from the dictionary which results in 28,981 number of unique        phrases.    -   Novas Phrases dictionary: The Novas Phrases dictionary was        created by mining anonymized Westlaw user logs with at least 6        years of log data where the Westlaw is an online legal research        service for lawyers and legal professionals in the United States        and the United Kingdom. After cleaning the data, 169,224 unique        phrases were gathered.

All text and phrases from dictionaries may be lowercased before thelooking up process.

Candidate phrases may be identified and chosen in steps. First, theinput text is cleaned, then features may be obtained for each multi-wordterm. Terms with the feature that meets a requirement or with a scoreabove a threshold will be kept to the next step.

To clean the input text, one approach is to remove the punctuation marksexcept for the comma(,), hyphen(-), apostrophes('), brackets(( )) anddollar sign($) from the text. Then, the cleaned input text may be splitinto n-grams where 2≤n≤4 by white space. The original case of the wordmay be kept as a feature of an n-gram.

Any number of features may be considered. For example, two features maybe considered for each candidate n-gram. In one example, the featuresconsidered are: capitalized concatenated sequence of words, a wayattorneys define a term which carries legal meanings; and TF×IDF featurewhich is a measure of an n-gram's frequency in a document compared toits rarity in general use. This can be used to remove noise n-grams thathave few appearances in a document and common n-grams that appear inalmost every document that does not carry legal meanings.

One way attorneys define a term is by concatenating a sequence ofcapitalized words. This kind of term is named as a “defined term” whichusually conveys legal meanings. Therefore, a rule may be set up toextract the defined terms is finding n-grams where each word iscapitalized. The n-grams that follow the rule are kept as goodkeyphrases.

Defined terms can usually be found at the beginning of a legal document,or at the beginning of a stand-alone section such as a schedule. Thefirst letter of each word in a defined term is capitalized so that thereader can identify that the meaning of the term is “different” orspecific and that he would interpret what he is reading in accordancewith the definition given. Once the defined terms are defined somewherein the document, the rest of the document will typically just refer theterm without redefining it.

Defined terms can be a problem for lawyers. For example, if a term isdefined in the 5th page of the document, by the time a reviewer reachesthe 100th page, they may forget the definition of the term, so they willhave to go back and find the definition on the 5th page. If they forgetthat it is defined on the 5th page, then further time will need to bespent finding the definition. Accordingly, in addition to identifyingand extracting defined terms, a useful tool provided by the presentinnovations is a “magnifier” tool for aiding review of legal documentsby providing a user interface that is configured to provide definitionsof defined terms at the time that those defined terms are displayed inthe body of the document, regardless of where in the document is beingcurrently reviewed and shown to the user.

The magnifier will first walk through the whole document, identify allthe defined terms and their associated definitions and remember them.Then, once a defined term is presented in the document, a box will bepopped up showing the definition of the term. Therefore, users will nothave to go back and try to search for where the term was defined.

FIG. 17 shows an example of a legal document containing a “OperatingCosts” defined term. FIG. 18 shows an example of a pop-up box presentedto a user in a user interface when the user is reviewing another portionof the document in which the defined term “Operating Costs” appears.

An example is shown in FIG. 21 of another user interface relayingvarious defined terms from a document being reviewed.

Detecting the defined terms and their definitions is not always an easytask due to the fact that there is no standard, unified way to createthe defined terms. When lawyers create a document, they tend to use adifferent style, and style can vary from jurisdiction to jurisdiction.Defined terms may be defined anywhere throughout a document with doublequotes or capitalized letters which may imply that setting up a rigidset of rules to find them may not be scalable.

In one approach, a two level review of a subject document may beconducted to determine whether defined terms are present and, if theyare, what they and their definitions are.

To determine whether defined terms are present, a universal languagemodel fine-tuning for text classification (ULMFit) model may be employedto indicate whether a piece of text contains defined terms ordefinitions. The model is a deep neural network that utilized the ideaof transfer learning which first builds a language model by using theWikipedia dataset to learn the relationships between words, then thelanguage model is fine-tuned by fitting in the domain-specific dataset,in our case, it's the legal documents. After this, the language modelwill update the relations between words that make sense in the legaldomain. After that, a downstream classification layer is added to theneural network to classify the input text.

Once text is identified that contains defined terms and definitions,they are extracted from the text. Two exemplary approaches for thisextraction include creating a list of regex patterns and training anentity recognizer. For example, FIG. 19 shows exemplary regex patternsthat may be deployed to identify and extract defined terms. Utilizingregex patterns and training an entity recognizer may also be used incombination to identify and extract defined terms and their definitions.

The TF×IDF feature compares the frequency of an n-gram's use in aparticular document with the frequency of that n-gram across the corpuswhich is represented by the number of documents containing the n-gram.The TF×IDF feature may be calculated for n-grams with a single n at atime instead of mixing 2≤n≤4 at the same time which shows betterperformance. The n-grams with TF×IDF score above a threshold are carriedto the next steps.

To further reduce noise, a list of linguistic patterns may be extractedfrom the aforementioned two dictionaries. The linguistic patterns may beextracted by concatenating the part-of-speech(POS) tag of each word in aphrase. Table 14 below shows examples of linguistic patterns

TABLE 14 Phrase Linguistic Pattern spurious interpretation ADJ NOUNproperty-disclosure statement NOUN PUNCT NOUN NOUN term to conclude NOUNPART VERB commercial letter of credit ADJ NOUN ADP NOUN

Lastly, a filter may be applied to select the key phrases that are mostrelevant to a particular focus of a user, for example commercial leases.Accordingly, a manually created list of topics may be compiled (e.g.,“lease”, “commercial”, “contracts”, etc.) and the semantic similaritybetween each of the candidate key phrases and the topics may becalculated. A threshold may be enforced to keep the ones with highsemantic similarity scores as a final list of key phrases.

After the process of the above steps on exemplary commercial leases, alist of 2-word phrases, 3-word phrases, and 4-word phrases may beobtained separately. These may be used in the other comparison andmatching applications described herein.

In another aspect, a tool is implemented to locate portions of adocument (spans of text) that may include the answer to a specific queryor question or be relevant to a particular topic. For example, in thecontext of a contract review, a user might be interested in an answer tothe question “Is the contract assignable?” or “What are theindemnification obligations?”. Questions may also be represented astopics—for example “assignment,” indemnification,” etc.

In one approach, each question is treated as a set of query words andeach text span as a document. In one example, a word embedding-basedtranslation language model is implemented. In this approach, documentsmay be ranked based on the probability that they are relevant to thequery q. Therefore, the Relevance Status Value (RSV) of the query q anddocument d is defined as:

RSV(q,d)=p(d|q)

Using Bayes rule, we have:

${RS{V\left( {q,d} \right)}} = \frac{{p\left( q \middle| d \right)}{p(d)}}{p(q)}$

Ignoring the constant p(q), and replacing d by its language model\theta_d (i.e., the probability distribution of terms of the vocabularyin d), we have

RSV(q,d)

_(rank) p(q|θ _(d))(p(d)

We use the clause type scores calculated by the binary classifiers asthe prior probability p(d) and use Dirichlet Language Model to estimatethe likelihood of query words in the document language model.

FIG. 22 shows an example of a user interface depicting the result of aquestion analysis and answer extraction tool.

In another aspect, a tool is implemented to identify particular factsfrom a document that may be relevant to a reviewer (“named facts”).Examples include rent amount, tenant and landlord names, premises,building, commencement date, etc. The searching, analysis and extractiontools identified herein may be employed for this purpose. An example isshown in FIG. 20 of a user interface relaying various named facts from adocument being reviewed.

The results of the comparison analyses may be rendered in a userinterface to assist a user in receiving, interpreting and analyzingresults. In one example, as an approximate user journey, the user may beenabled to pick a question in a task list. The relevant language in thereview lease will then be displayed. When the user has clicked on apiece of language, they may want to see the comparable language in thestandard lease. From there they may be enabled to opt to view anyavailable deviation analysis functions (such as the many types describedherein) to help them analyze the difference between the two provisions,such as a word difference or obligation analysis.

For example, upon clicking on language found in a review document thathas been determined to be relevant to or a match to a particularquestion or topic, a user may be shown in a user interface:

-   -   1. All standard answers for the equivalent question. This may be        configured to show a user all the standard answers available in        chronological (reading) order. This is a safety net. It reduces        the risk of the user missing something. Word diff will be        available on all standard answers to every language hit in the        review document (so if there are 5 hits and 3 standard answers,        there will be 15 comparable matches shown); and/or    -   2. Any “highly comparable” standard answers. This may be        configured to highlight to a user those standard answers that        seem the most comparable to the particular hit in the review        document that the user is reviewing at the time.

When the user clicks onto a next question or topic answer, they may beshown revised highlighting for option 2 above. For simple scenarioswhere there is only one language hit from the review document and acorresponding standard answer, then there may be no need for option 2 tobe available to the user.

Word Diff

For each sentence in the review document that does have a counterpart inthe standard, we compute word differences via the simple,well-established long string diff method, which identifies all changesin the text. To reduce visual overload we included an options for hidingminor types of changes, either involving addition/deleting of words froma user-provided list (e.g. “the”, “a” and “an”), or small linguisticvariations (e.g. “is” vs “are”). We call the underlying detection methodSmart Word Diff.

The Word Diff module, based on the standard Python difflib module,serves as the baseline method to display relevant diffs of a pair-wisecomparison to the user. FIG. 13 shows an example of the output of thealgorithm in an exemplary user interface. The algorithm works by findingthe longest common subsequence (“LCS”) of two texts—this is the first“match” or “alignment” of the sentence. It then applies LCS again to thetext before the first “match” and to the text after the first “match”.This process may continue recursively after each match. Any text that isunmatched or unaligned becomes a diff.

This approach may be improved by 1.) switching sentence tokenization touse the spaCy implementation rather than nitk, 2.) using lemmatization,and 3.) ignoring section clause numbers. In another example, alinguistic resource like WordNet may be used in order to give thealgorithm knowledge of synonym sets—therefore a change like“Premises”->“Property” or “Tenant->“Resident” would be seamlesslytreated as matched text, lessening the overall amount of text a user hasto inspect.

In another exemplary approach, a smarter ranked diff is used whichcategorizes textual difference into relevancy categories. For example,“the”, “an”, “a” would be treated as irrelevant differences while “not”,“but” and “and” (which are usually considered stopwords) are treated asrelevant. We went about classifying diffs as relevant/not relevant indifferent ways. One was to used Machine Learning technique known asfeature selection. This approach uses labeled data to find featureswhich are most associated with a particular label. The specific approachwe used was Mutual Information (See FIG. 3 for an example). Another wayto classify diffs was to create expert lists of relevant and irrelevantwords and aggregate the relevancy into a sentence-level score.

Multi-Sentence Matching and Comparison

A key part of the analysis is to map the similar sentences between thetwo documents and detect their deviations. This mapping could result ina sentence of the review document being mapped to multiple sentences ofthe standard document (many-to-one) and vice versa (one-to-many). FIG. 9illustrates a many-to-one example.

The goal of this analysis is to explore ways to align many-to-onematching sentences (meaning aligning their matching segments asillustrated by the grayscale underlining in FIG. 9) and performdeviation detection (display the words/segments that are different, redtext in FIG. 9). The one-to-many alignment problem is effectivelyidentical and only differs in how it should be displayed for the user.

FIG. 10 shows how the multi-sentence deviation detection (MSDD) modulemay be positioned in an analysis pipeline. The input to the MSDD moduleis a target sentence from the standard document and a list of matchedsentences from the review document, while the decision about thematching has been performed upstream (by the sentence matching anddeviation scoping modules).

The output of the MSDD module is the identified deviations in the formof the indices of non-aligned tokens for each sentence in thecomparison, both from the standard and the review documents (the redtext in FIG. 9).

As shown in FIG. 10, the MSDD module uses the deviation detectiontechniques available in the pipeline. Additional ways of deviationdetection have also been explored and will be described below.

The following matching depicted in Table 15 will be used hereafter todemonstrate the performance of the different methods used for themulti-sentence deviation detection module.

TABLE 15 Standard Document Review Document 3.2.1 Immediately after theend of the term 2.3 The Tenant shall comply with all laws (andnotwithstanding that the term has relating to the Rights and allreasonable ended), the Tenant shall make an regulations in connectionwith the exercise application to remove all entries on the of the Rightsthat the Landlord may make Landlord's title relating to the easementsfrom time to time and notify to the Tenant granted by this lease andshall ensure that in writing, and immediately after the end of anyrequisitions raised by HM Land the term, the Tenant shall make anRegistry in connection with that application application to remove allentries on the are dealt with promptly and properly. Landlord 's titlerelating to the easements 3.2.2 The Tenant shall keep the Landlordgranted by this lease and shall ensure that informed of the progress andcompletion of any requisitions raised by HM Land its application.Registry in connection with that application 3.3 The Tenant shall adhereto all laws are dealt with promptly and properly and relating to theRights and all reasonable the Tenant shall keep the Landlord regulationsin connection with the exercise informed of the progress and completionof of the Rights that the Landlord may make its application. from timeto time and notify to the Tenant in writing.

The MDSS was tested using gold data, meaning sentences that have beenalready matched from the expert and were therefore indeed matchingsentences.

In one example, shown in Table 16, MDSS uses difflib and concatenatedsentences. From the difflib package documentation: “the basic algorithmpredates, and is a little fancier than, an algorithm published in thelate 1980's by Ratcliff and Obershelp under the hyperbolic name “gestaltpattern matching.” The idea is to find the longest contiguous matchingsubsequence that contains no “junk” elements (the Ratcliff and Obershelpalgorithm doesn't address junk). The same idea is then appliedrecursively to the pieces of the sequences to the left and to the rightof the matching subsequence. This does not yield minimal edit sequences,but does tend to yield matches that “look right” to people.”

TABLE 16 MDSS using difflib and concatenated sentences. Deviationshighlighted in underline. Standard Document Review Document 3.2.1Immediately after the end of the term 2.3 The Tenant shall comply withall laws (and notwithstanding that the term has relating to the Rightsand all reasonable ended), the Tenant shall make an regulations inconnection with the exercise application to remove all entries on the ofthe Rights that the Landlord may make Landlord's title relating to theeasements from time to time and notify to the Tenant granted by thislease and shall ensure that in writing, and immediately after the end ofany requisitions raised by HM Land the term, the Tenant shall make anRegistry in connection with that application application to remove allentries on the are dealt with promptly and properly. Landlord 's titlerelating to the easements 3.2.2 The Tenant shall keep the Landlordgranted by this lease and shall ensure that informed of the progress andcompletion of any requisitions raised by HM Land its application.Registry in connection with that application 3.3 The Tenant shall adhereto all laws are dealt with promptly and properly and relating to theRights and all reasonable the Tenant shall keep the Landlord regulationsin connection with the exercise informed of the progress and completionof of the Rights that the Landlord may make its application. from timeto time and notify to the Tenant in writing,

Firstly, the SequenceMatcher class of the difflib package has beenapplied to the comparison of the one sentence of the review documentagainst a single sentence that was the result of concatenation of themany review sentences.

In another example, shown in Table 17, MDSS uses difflib and independentsentence comparison.

TABLE 17 MDSS using difflib and independent sentence comparison results.Deviations highlighted in underline. Standard Document Review Document3.2.1 Immediately after the end of the term 2.3 The Tenant shall complywith all laws (and notwithstanding that the term has relating to theRights and all reasonable ended), the Tenant shall make an regulationsin connection with the exercise application to remove all entries on theof the Rights that the Landlord may make Landlord's title relating tothe easements from time to time and notify to the Tenant granted by thislease and shall ensure that in writing, and immediately after the end ofany requisitions raised by HM Land the term, the Tenant shall make anRegistry in connection with that application application to remove allentries on the are dealt with promptly and properly. Landlord 's titlerelating to the easements 3.2.2 The Tenant shall keep the Landlordgranted by this lease and shall ensure that informed of the progress andcompletion of any requisitions raised by HM Land its application.Registry in connection with that application 3.3 The Tenant shall adhereto all laws are dealt with promptly and properly and relating to theRights and all reasonable the Tenant shall keep the Landlord regulationsin connection with the exercise informed of the progress and completionof of the Rights that the Landlord may make its application. from timeto time and notify to the Tenant in writing.

Comparing independently each sentence of the standard document to thesentence of the review document yields better results as the approach isnot sensitive to the sentence order of appearance. Another benefit ofusing the difflib approach in general is the fact that theSequenceMatcher provides an indication of the 1-1 matched sentencesegments as indicated for example by the grayscale underlining in FIG.9. This is a useful aid to identify how was the optimal alignmentperformed and potentially for visualization purposes in the GUI.

In another example, a symmetric difference of feature sets from apretrained count vectorizer may be employed. For this approach, apretrained count vectorizer was used to extract features (tokens andbigrams) from the compared sentences. The count vectorizer is part ofthe sklearn library and it was created using three sample leases. Theextracted features from the standard document sentences were considereda common set and compared to the set of features of the sentence of thereview document. Tokens belonging in the difference of the two sets werethen marked in underline (Table 18). This approach has the benefit ofbeing less visually overwhelming especially for common words that areless likely to change the meaning of the sentences such as stop words.

TABLE 18 Symmetric difference of sets of sentence(s) tokens. StandardDocument Review Document 3.2.1 Immediately after the end of the term 2.3The Tenant shall comply with all laws (and notwithstanding that the termhas relating to the Rights and all reasonable ended), the Tenant shallmake an regulations in connection with the exercise application toremove all entries on the of the Rights that the Landlord may makeLandlord's title relating to the easements from time to time and notifyto the Tenant granted by this lease and shall ensure that in writing,and immediately after the end of any requisitions raised by HM Land theterm, the Tenant shall make an Registry in connection with thatapplication application to remove all entries on the are dealt withpromptly and properly. Landlord 's title relating to the easements 3.2.2The Tenant shall keep the Landlord granted by this lease and shallensure that informed of the progress and completion of any requisitionsraised by HM Land its application. Registry in connection with thatapplication 3.3 The Tenant shall adhere to all laws are dealt withpromptly and properly and relating to the Rights and all reasonable theTenant shall keep the Landlord regulations in connection with theexercise informed of the progress and completion of of the Rights thatthe Landlord may make its application. from time to time and notify tothe Tenant in writing.

Multi-sentence deviation detection may be improved by various means. Forexample, data pre-processing may be accomplished by normalizing inputdata by lowercasing, removing clause list items in the beginning of thesentences (i.e. a), b), iii), 12.1 etc), removing numbers andpunctuation. This function may be moved upstream of the matching task.

In another example, a custom stop word list may be used, derived from adefault stop word list included in the NLTK python package but excludingall negation-related terms. This may be implemented in the “Smart Diff”module discussed herein.

In another example, stemming and lemmatization are employed. In yetanother example, synonyms may be identified and used in the analysis.

As an exemplary alternative to difflib, the Fuzzy Match algorithm may beused. While difflib aligns sentence segments only when they areidentical, the goal of the Fuzzy Match is to align the matching sentencesegments based on a similarity score. The Fuzzy Match algorithm performsthe alignment using dynamic programming inspired by the Longest CommonSubsequence (LCS) algorithm with the difference that the similaritybetween two tokens now corresponds to the cosine similarity of the tokenvectors obtained by Spacy (see section Synonyms and Semantics usingSpacy language model). For two sentences of m and n number of tokensrespectively, we calculate the score at each position of the matrix M asfollowing, where skip_penalty is a small penalty for mismatches outsidea diagonal and unmatched threshold is a parameter that allows only highsimilarity scores to contribute to the alignment path.

FIG. 11 shows a heatmap representation of matrix M for the alignment ofthe sentences “The tenant must also pay all costs, including reasonableattorney fees, related to the eviction.” and “This includes attorneyfees for the eviction.” Higher scores are represented in the blue colorrange while lower similarities scores are in the red color range. Asprogressively the alignment improves by encountering similar words, theoverall score of the alignment also increases as indicated by the valueand the color of the respective cell.

After constructing matrix M, we can retrace the best segment alignmentby starting at cell M[m,n], the last cell of the table, and follow thescoring path that leads to that cell by adding tokens whenever we aremoving on the diagonal as long as the move has led to an increased score(FIG. 12). For the example shown in FIGS. 11 and 12, the matchedsegments tokens are {includes, attorney, fees, the, eviction} and{including, attorney, fees, the, eviction}.

Obligation Change/Deviation Detection

To further reduce visual overload, and categorize changes in ameaningful way, we introduced the concept of Obligation ChangeDetection. The obligation change detection module provides a novelmechanism for linguistic comparison at the conceptual (rather than puresyntactic) level. Given a standard and a review sentence, we firstidentify key linguistic building blocks like actor, main obligation, andany restrictions or conditions. Second, we categorize differences withrespect to these building blocks (e.g. additional/missing obligation),allowing us to flag types of changes in a meaningful way, as shown inthe examples depicted in FIG. 3.

As shown in FIG. 23, a first step of an obligation analysis is todetermine whether a given sentence contains an obligation and, if so, toextract its various components.

In one example, this requires obtaining a dependency parse of the inputtext. Dependency parsing aims to represent the grammatical structure ofa sentence as a set of one-to-one relationships between words.

FIG. 24 shows a dependency parse structure of the sentence: “The Tenantmust keep the property in good condition”. This is a simplifiedrepresentation as noun chunks (e.g. “The Tenant”) have been groupedtogether. In this example, the verb “keep” is the root of the tree, andall other phrases are either directly or indirectly connected to it viarelationships called dependencies.

In one implementation, rules-based logic underlying obligationextraction works as follows. First, the dependency parse of the inputsentence is obtained.

Then, the sentence type may be classified (e.g., infinitive, modal ornone). For example, the sentence may be checked for acceptable modalkeywords. A modal keyword is a “can”, “must”, “shall”, “will” or “may”that is the auxiliary of a verb that has a nominal subject such as “theLandlord” or “the Tenant”. As another example, the sentence may bechecked for the presence of an infinitive verb token. An infinitive verbtoken is tagged as a verb and is preceded by the (non-passive) auxiliary“to”.

Then, obligations may be extracted. For example, a sentence may bechecked for the presence of an agent if one exists. For example, if thesentence is modal, a tool may be configured to check if there is a tokenthat is the nominal subject of the first modal or verb token (extractedpreviously) with a subtree that contains an actor keyword such as“landlord” or “tenant.” As another example, if the sentence isinfinitive, a tool may be configured to check tokens preceding the mainverb (extracted previously) for a match with any of the actor keywords.

Obligation text spans may be extracted. For example, if the sentence ismodal, for each modal/verb token pair, a span may be identified startingfrom each modal token and ending with the rightmost child of the verbtoken. As another example, if the sentence is infinitive, and if thereis only one obligation in the sentence, the entire sentence may beidentified as the obligation span. Otherwise, if there are multipleobligations connected by the conjunction “and,” the sentence may besplit around the conjunction.

Then, the modality of each obligation may be extracted based on, forexample, the modal verb and whether it is preceded by the word “not.”

Then, restriction spans may be extracted by searching the sentence forrestriction trigger words (e.g., “except”, “subject to”, “without theconsent”, “provided that”, “if”, “unless”).

Once extracted, obligations may be sanitized and compared to one anotherfor changes or deviations, as shown in FIG. 25. Obligations may differfrom one another in a number of different semantic and logical ways.FIG. 3 (described above) provides exemplary depictions of obligationcomparisons. More examples are shown in Table 19.

TABLE 19 Change/ Deviation Type Indication Change in agent if the actorof the obligation has changed Missing an obligation is present in thestandard obligation lease sentence but not in the review lease sentenceAdditional an obligation is present in the review lease obligationsentence but not in the standard lease sentence Missing a restriction ispresent in the standard lease restriction sentence but not in the reviewlease sentence Additional a restriction is present in the review leaserestriction sentence but not in the standard lease sentence ModalityModality refers to an obligation category change produced by theObligation Extractor. The possible classes/categories of modality maybe, for example: Permission: Tenant may assign the whole of thePremises. Forbiddance: Tenant may not assign the whole of the Premises.Obligation: Tenant must keep the Premises clean and tidy. No Obligation:Tenant is not liable for repairs.

To detect these changes and deviations, different analyses may bedeployed. For example, as shown in FIG. 25, an agent change may bedetected, a modality change may be detected, missing and additionalobligations may be detected, and missing and additional restrictions maybe detected.

A comparison module may be responsible for calling an obligationextractor on a pair of input sentences and then running the methodsbelow to obtain deviation results. The module also may be configured todetermine the spans that need to be highlighted in the user interfaceand prepare a dictionary as an output which can be easily serialized toJSON and passed back to the calling deviation service layer.

Agent change detection may be accomplished in one or more steps. Forexample, a preprocessing step and a fuzzy string matching step may beemployed. In the first step, we apply a rule to resolve anaphora such as“Both parties” to a more common string such as “The Tenant and theLandlord”. In the second step we use the SequenceMatcher ratio( ) methodto detect similar agents (2*M/T) where M is number of “matches” found bySM and T is number of elements in two strings. Similarity metricsprovided by fuzzywuzzy library (calculate similarity of two stringsbased on the Levenshtein edit distance) may also be employed.

An extracted obligation (like an extracted restriction) is generally asubstring of the entire sentence from which it was extracted. In orderto detect additional or missing obligations, one exemplary approach isto transform each obligation to tf-idf vectors and reuse a sentencematching module. In this step, for each standard obligation, we selectthe single best obligation match from the review side; each “match” isdetermined using a threshold that is set by hand. Any obligation on thestandard side that is unmatched is considered a missing obligation. Anyunmatched obligation on the review side is an additional obligation.

Analysis of restrictions may be configured to use the same exactmechanism as missing/additional obligation detection, with an additionalstep to double-check any unmatched restrictions (these are potentialdeviations). For each unmatched restriction, we use fuzzy substringsearch implemented with SequenceMatcher class ratio( ) method (similarto agent change detection). If the method determines the restriction isa substring of the opposite side, we remove it from the list ofdeviations to avoid confusing/incorrect output.

Modality change detection may be configured as an equality check of theextractor's modality category of matched obligations. The module maythen determine the character spans to be highlighted as this deviationtype requires highlighting on both standard and review side.

Of course, multiple different types of obligation changes or deviationsmay be detected and signaled to a user via a user interface. Forexample, FIG. 26 shows an example of a standard lease term comparedagainst a review lease with multiple changes detected.

While categorizing changes in the above described manner helps withprioritization and triage of review, it does not necessarily give adefinite indication of the risk or impact of the change, as this wouldnot only require full semantic text comparison but also an indication ofwhat the specific client cares about for the review. We leave thisinterpretation step to the expert user.

The systems and methods described herein may be embodied in a standalonesystem, a system accessible by other systems or any combination. Forexample, in a standalone system embodiment, the tools for detectingdeviations among documents and portions thereof, extracting informationfrom documents and portions thereof, and detecting deviations betweenobligations in documents and portions thereof may be comprised in astandalone application residing on a user's computing device or accessedvie a network or internet link from the user's device. Such a standaloneapplication may be configured to obtain standard documents such asstandard playbooks or standard contracts from a contract analytics toolor other library through a web, network and/or API link, for example.Such an application may be configured to create user dashboards,visualizations and detection result exports. Such an application may beconfigured to interact with another application configured to performany of the steps described herein.

The systems and methods described herein may also be embodied in aservice accessible to other applications via a web, network or API link.For example, a contract evaluation tool may be configured to access aservice that provides tools for detecting deviations among documents andportions thereof, extracting information from documents and portionsthereof, and detecting deviations between obligations in documents andportions thereof independently via an API.

FIGS. 1 through 26 are conceptual illustrations allowing for anexplanation of the present disclosure. It should be understood thatvarious aspects of the embodiments of the present disclosure could beimplemented in hardware, firmware, software, or combinations thereof. Insuch embodiments, the various components and/or steps would beimplemented in hardware, firmware, and/or software to perform thefunctions of the present disclosure. That is, the same piece ofhardware, firmware, or module of software could perform one or more ofthe illustrated blocks (e.g., components or steps).

In software implementations, computer software (e.g., programs or otherinstructions) and/or data is stored on a machine readable medium as partof a computer program product, and is loaded into a computer system orother device or machine via a removable storage drive, hard drive, orcommunications interface. Computer programs (also called computercontrol logic or computer readable program code) are stored in a mainand/or secondary memory, and executed by one or more processors(controllers, or the like) to cause the one or more processors toperform the functions of the disclosure as described herein. In thisdocument, the terms “machine readable medium,” “computer program medium”and “computer usable medium” are used to generally refer to media suchas a random access memory (RAM); a read only memory (ROM); a removablestorage unit (e.g., a magnetic or optical disc, flash memory device, orthe like); a hard disk; or the like.

Notably, the figures and examples above are not meant to limit the scopeof the present disclosure to a single embodiment, as other embodimentsare possible by way of interchange of some or all of the described orillustrated elements. Moreover, where certain elements of the presentdisclosure can be partially or fully implemented using known components,only those portions of such known components that are necessary for anunderstanding of the present disclosure are described, and detaileddescriptions of other portions of such known components are omitted soas not to obscure the disclosure. In the present specification, anembodiment showing a singular component should not necessarily belimited to other embodiments including a plurality of the samecomponent, and vice-versa, unless explicitly stated otherwise herein.Moreover, the applicant does not intend for any term in thespecification or claims to be ascribed an uncommon or special meaningunless explicitly set forth as such. Further, the present disclosureencompasses present and future known equivalents to the known componentsreferred to herein by way of illustration.

The foregoing description of the specific embodiments so fully revealsthe general nature of the disclosure that others can, by applyingknowledge within the skill of the relevant art(s), readily modify and/oradapt for various applications such specific embodiments, without undueexperimentation, without departing from the general concept of thepresent disclosure. Such adaptations and modifications are thereforeintended to be within the meaning and range of equivalents of thedisclosed embodiments, based on the teaching and guidance presentedherein. It is to be understood that the phraseology or terminologyherein is for the purpose of description and not of limitation, suchthat the terminology or phraseology of the present specification is tobe interpreted by the skilled artisan in light of the teachings andguidance presented herein, in combination with the knowledge of oneskilled in the relevant art(s).

In order to address various issues and advance the art, the entirety ofthis application for SYSTEMS AND METHODS FOR DEVIATION DETECTION,INFORMATION EXTRACTION AND OBLIGATION DEVIATION DETECTION (including theCover Page, Title, Abstract, Headings, Cross-Reference to RelatedApplication, Background, Brief Summary, Brief Description of theDrawings, Detailed Description, Claims, Figures, and otherwise) shows,by way of illustration, various embodiments in which the claimedinnovations may be practiced. The advantages and features of theapplication are of a representative sample of embodiments only, and arenot exhaustive and/or exclusive. They are presented only to assist inunderstanding and teach the claimed principles. It should be understoodthat they are not representative of all claimed innovations. As such,certain aspects of the disclosure have not been discussed herein. Thatalternate embodiments may not have been presented for a specific portionof the innovations or that further undescribed alternate embodiments maybe available for a portion is not to be considered a disclaimer of thosealternate embodiments. It will be appreciated that many of thoseundescribed embodiments incorporate the same principles of theinnovations and others are equivalent. Thus, it is to be understood thatother embodiments may be utilized and functional, logical, operational,organizational, structural and/or topological modifications may be madewithout departing from the scope and/or spirit of the disclosure. Assuch, all examples and/or embodiments are deemed to be non-limitingthroughout this disclosure. Also, no inference should be drawn regardingthose embodiments discussed herein relative to those not discussedherein other than it is as such for purposes of reducing space andrepetition. For instance, it is to be understood that the logical and/ortopological structure of any combination of any program components (acomponent collection), other components and/or any present feature setsas described in the figures and/or throughout are not limited to a fixedoperating order and/or arrangement, but rather, any disclosed order isexemplary and all equivalents, regardless of order, are contemplated bythe disclosure. Furthermore, it is to be understood that such featuresare not limited to serial execution, but rather, any number of threads,processes, services, servers, and/or the like that may executeasynchronously, concurrently, in parallel, simultaneously,synchronously, and/or the like are contemplated by the disclosure. Assuch, some of these features may be mutually contradictory, in that theycannot be simultaneously present in a single embodiment. Similarly, somefeatures are applicable to one aspect of the innovations, andinapplicable to others. In addition, the disclosure includes otherinnovations not presently claimed. Applicant reserves all rights inthose presently unclaimed innovations including the right to claim suchinnovations, file additional applications, continuations, continuationsin part, divisions, and/or the like thereof. As such, it should beunderstood that advantages, embodiments, examples, functional, features,logical, operational, organizational, structural, topological, and/orother aspects of the disclosure are not to be considered limitations onthe disclosure as defined by the claims or limitations on equivalents tothe claims. It is to be understood that, depending on the particularneeds and/or characteristics of an individual and/or enterprise user,database configuration and/or relational model, data type, datatransmission and/or network framework, syntax structure, and/or thelike, various embodiments may be implemented that enable a great deal offlexibility and customization. While various embodiments and discussionshave included reference to applications in the legal context, and morespecifically in the context of contract review, it is to be understoodthat the embodiments described herein may be readily configured and/orcustomized for a wide variety of other applications and/orimplementations.

What is claimed is:
 1. A method for extracting information, comprising:receiving an input text; splitting the input text into n-grams whileretaining a case of words as a feature; for each n-gram, determiningwhether it is a capitalized concatenated sequence of words andcalculating a frequency of the n-gram's appearance in the input textrelative to how rarely the n-gram is used in general use; identifying asa defined term each n-gram that is a capitalized concatenated sequenceof words and has a relative frequency above a predetermined threshold;identifying a definition of each defined term from the input text; anddisplaying the definition of a defined term while also displaying aportion of the input text in which the defined term appears but that isdifferent from a portion of the input text identified as the definitionof the defined term.
 2. The method of claim 1, further comprisingcleaning the input text before the input text is split into n-grams byat least removing punctuation marks except for a predetermined pluralityof punctuation marks to be retained.
 3. The method of claim 1, whereinthe definition of a defined term is not displayed until a view of theinput text is scrolled to display the portion of the input text in whichthe defined term appears but that is different from a portion of theinput text identified as the definition of the defined term.
 4. Themethod of claim 1, wherein defined terms are displayed together with theinput text even if the defined terms are not present in a currentlydisplayed portion of the input text.
 5. The method of claim 1, whereinthe defined terms are highlighted where they appear in a display of theinput text.
 6. A method for extracting information, comprising:receiving a standard text and a review text; analyzing the standard textand the review text to identify portions of those texts relevant to aninput point of interest; and displaying in a user interface a portion oftext identified in the review text as relevant to the point of interestwhile also displaying any deviations therein from a portion of textidentified in the standard text as being relevant to the point ofinterest.
 7. The method of claim 6 wherein the point of interest is oneof a question, a topic, a named fact and a defined term.
 8. The methodof claim 6, wherein the deviations are not displayed until a user clickson the displayed portion of text identified in the review text as beingrelevant to the point of interest.
 9. The method of claim 6, wherein theportion of text identified in the standard text as being relevant to thepoint of interest is displayed upon a user clicking the portion of textidentified in the review text as being relevant to the point ofinterest.
 10. The method of claim 6, wherein multiple portions of textare identified in the standard text as being relevant to the point ofinterest and are displayed upon a user clicking the portion of textidentified in the review text as being relevant to the point ofinterest.
 11. The method of claim 10 wherein any deviations between theportion of text identified in the review text as being relevant to thepoint of interest and each of the multiple portions of text areidentified in the standard text as being relevant to the point ofinterest and are displayed.
 12. The method of claim 6 wherein theanalysis of the standard text and the review text to identify portionsof those texts relevant to an input point of interest includes usingwords of the input point of interest as query words and estimating alikelihood of those query words in document language modelsrepresentative of portions of the reference text and portions of thestandard text.
 13. The method of claim 6 wherein points of interest aredisplayed on the user interface and the portion of text identified inthe review text as relevant to a particular point of interest is notdisplayed until a user click s on the display of that particular pointof interest.